Adjustment device for a clutch with load moment lock

ABSTRACT

The invention relates to an adjustment device for producing a rotational movement that comprises an output element ( 3 ) that can be adjusted at an angle by actuating a drive element ( 2 ). The adjustment device further comprises a load moment lock ( 1 ) interposed between the drive and the output element ( 2, 3 ) that frictionally blocks a rotational movement initiated at the output element side and that transmits a rotational movement initiated at the drive element side to the output element ( 3 ). Said load moment lock ( 1 ) further comprises locking elements ( 4, 4 ′) that are disposed in a cylindrical adjustment housing ( 10 ). Upon the effect of a play-compensating device ( 5 ) that is at least partially interposed between opposite adjusting surfaces ( 41, 41 ′) of the locking elements ( 4, 4 ′) and that compensates the rotational angle play between the drive element ( 2 ), the output element ( 3 ) and the load moment lock ( 1 ), the clamping surfaces ( 43, 43′, 43″, 43 ′″) are forced apart with such a force that they rest against the adjustment housing ( 10 ) with a predetermined pre-load. The adjustment device is provided with a play-compensating device ( 5 ) that for both directions of rotation radially.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of International application numberPCT/DE00/03935, filed Nov. 3, 2000, which in turn claims priority ofGerman application number 199 54 232.5, filed Nov. 4, 1999.

BACKGROUND

The invention relates to an adjustment device for a clutch with a loadmoment lock.

An adjustment device with a load moment lock is known from DE 41 20 617C2 through which torque on the drive side is transferred in bothdirections to an output element whilst torque on the output side isblocked in both directions by the load moment lock and the force isdirected into an adjustment housing and is therefore not transferred tothe drive element.

Torque on the drive side is transferred between the drive element andthe load moment lock by means of elements which engage in each otherwith keyed connection. Since the position of the locking elements of theload moment lock changes through tolerance and wear as a result of highsurface pressure, for the functional reliability of the known adjustmentdevice it is necessary to incorporate a large amount of play so thatrotational angle play is present between the interengaging elementsconditional on the function without which a stepped transfer or changeof direction of the torque on the drive side is not possible. A minimumrotational angle play must also therefore be present between theinterengaging elements of the drive element and load moment lock inorder to prevent any wear and to permit a certain elastic deformation.

However too much rotational angle play, particularly with a steppedtransfer of the torque on the drive side, becomes unacceptablynoticeable since the rotational angle play causes a correspondinglylarge idling path or idling stroke of the drive element. Moreover whenreversing movement too much rotational angle play can lead totroublesome reverse play and to inaccurate handling.

The known adjustment device has a relatively larger reverse play in thebrake unit conditioned by tolerances in the component parts. In order torestrict this it is necessary to carry out production accurately withina narrow tolerance band. The assembly of the individual component partswhich are provided with low tolerances is expensive since the componentparts which are to be connected together have to be positioned preciselyrelative to each other.

In order to minimize the rotational angle play between a drive element,an output element and a load moment lock and to ensure a secure force ortorque transfer without any additional adjustment of the rotationalangle play during assembly or re-adjustment of the rotational angle playafter longer use, an adjustment device is proposed in the prior patentapplication 199 26 994.7 wherein between the drive element and the loadmoment lock or between the output element and the load moment lock thereis a play compensating device which compensates the rotational angleplay between the drive element, the output element and the load momentlock and with which the functionally conditioned rotational angle playbetween the drive element and the load moment lock or the load momentlock and the output element is automatically set and adjustedrespectively.

To this end the load moment lock has in a cylindrical adjustment housingtwo locking elements arranged in pairs in two planes one above the otherwherein the clamping faces through the action of the play compensatingdevice bear against the adjustment housing with a predeterminedpretension in that the play compensating device is arranged at least inpart between the opposing expanding faces of the pairs of lockingelements and forces the pairs of locking elements apart. The torqueintroduced on the output side increases the contact pressure of theclamping faces and thus of the pairs of locking elements against theadjustment housing.

The play compensating device furthermore serves to ensure the lockingelements bear against the adjustment housing with the predeterminedpretensioning force and to ensure an automatic re-adjustment whichbecomes necessary through wear on the component parts. It can consistfor example of a wedge mounted between the expanding faces of the pairsof locking elements, whereby the wedge faces lie opposite the expandingfaces of the pairs of locking elements and the wedge is guideddisplaceable with a wedge guide with keyed engagement in a slide guideof the drive element and is pretensioned radially by means of a springso that the wedge faces rest against the expanding faces free of play.Alternatively the play compensating device can be formed as acylindrical roller or ball or as an eccentric which is mounted rotatablebetween the expanding faces of the locking elements and is preferablydesigned as a stepped bolt.

An automatic adjustment of a minimum rotational angle play thereby takesplace in both directions of rotation of the adjustment device takinginto consideration the tolerances in the component parts and anautomatic readjustment takes place to account for any wear on thecomponent parts so that a minimum idling stroke is guaranteed duringoperation in both directions of rotation and high functional reliabilityis ensured for the adjustment device taking into account unavoidablewear. The manufacture of the individual component parts is thusconsiderably more cost-effective, assembling the adjustment devicebecomes easier and waste is restricted to a minimum.

SUMMARY

The object of the present invention is to provide an adjustment devicewith optimum rotational angle play between a drive element, an outputelement and a load moment lock which during assembly requires noadjustment and even after longer use requires no re-adjustment of therotational angle play and which can be constructed simply and inspace-saving manner.

The solution according to the invention provides an adjustment devicewhich ensures optimum rotational angle play between a drive element, anoutput element and a load moment lock and which requires neitheradjustment during assembly nor re-adjustment of the rotational angleplay even after longer use. Since the locking elements are only arrangedin one plane of the load moment lock the adjustment device can beconstructed very easily and in space-saving manner, although there is achange-over play when changing over from one adjustment direction intothe other.

Preferably the play compensating device has wedge faces which bearagainst the output element and/or against the locking elements, and atleast one spring which pretensions the play compensating deviceperpendicularly to the axis of the load moment lock in the sense ofreducing the distance between the play compensating device, the outputelement and the locking elements.

Through the wedge faces in connection with the pretensioning force ofthe spring the locking element faces are constantly brought to bearagainst the cylindrical adjustment housing and thus optimum rotationalangle play is guaranteed during setting up and even after longer termuse of the adjustment device.

In order to avoid any resetting of the locking element surfaces whichwould break down the contact between the locking element surfaces andthe cylindrical adjustment housing after operation of the adjustmentdevice, the wedge faces include such an angle with the axis of symmetryof the load moment lock that the connection is self-locking between theplay compensating device on the one hand and the output element and/orthe locking elements on the other hand.

The wedge faces can be provided selectively between the playcompensating device and the output element and/or between the playcompensating device and the locking elements. In a first embodiment ofthe invention the wedge faces of the play compensating device bearagainst counter wedge faces of the output element and substantially flatfaces of the play compensating device bear against the facing expandingfaces of the locking elements or parts of the expanding faces.

The output element can have protrusions or curvatures formed symmetricalwith the axis of symmetry of the load moment lock for spot or linearcontact with substantially rectilinear or inclined surfaces of the playcompensating device.

Correspondingly in a second embodiment of the invention the wedge facesof the play compensating device bear against the protrusions orcurvatures of the output element and substantially flat surfaces of theplay compensating device bear against the facing expanding faces of thelocking elements or parts of the expanding faces.

In a third embodiment of the invention the wedge faces of the playcompensating device bear against inclined expanding faces of the lockingelements and the substantially rectilinear faces of the playcompensating device bear against the protrusions or curvatures of theoutput element.

A further development of the solution according to the invention ischaracterised in that the drive element has claws which in the event oftorque on the drive side after removal of the frictional contact betweenthe locking elements and the adjustment housing engage with keyedconnection in recesses of the output element and entrain the latter inthe drive direction.

As an alternative to this the drive element can have recesses which inthe event of torque on the drive side after removal of the frictionalcontact between the locking elements and the adjustment housing bearwith keyed engagement against claws of the output element and entrainsame in the drive direction.

With both variations after the frictional contact between the lockingelements and adjustment housing has been lifted through the action oftorque on the drive side a positive locking connection is producedbetween the drive element and the output element and thus a slip-freeconnection is established between the drive element and output element.

BRIEF DESCRIPTION OF THE DRAWINGS

The idea on which the invention is based will now be explained infurther detail with reference to the embodiments illustrated in thedrawings in which:

FIG. 1 shows a cross-sectional view through a load moment lock having apair of locking elements and a device for compensating the play betweenthe drive element, the output element and the load moment lock withadjoining wedge faces of the play compensating device and outputelement;

FIG. 2 shows a cross-section through a load moment lock as in FIG. 1with a play compensating device with wedge faces of the playcompensating device bearing against protrusions or curvatures of theoutput element; and

FIG. 3 shows a cross-section through a load moment lock as in FIGS. 1and 2 with a play compensating device with wedge faces of the playcompensating device and the locking elements contacting one another.

DETAILED DESCRIPTION

The diagrammatic illustrations of the load moment locks in FIGS. 1 to 3show different embodiments of adjustment devices with a pair of lockingelements mounted in a plane of the load moment lock and a device forcompensating play between the drive element, the output element and theload moment lock. The reference numerals used coincide in all threefigures where they relate to the same component parts or component partshaving the same function, and only differ through the addition of aletter (a, b or c) for the different embodiments of the invention.

FIG. 1 shows a section through an adjustment device which operates onboth sides and has an adjustment housing 10 (shown in shaded lines) inwhich the functional parts of a load moment lock 1 a having automaticplay compensation are mounted. In the adjustment housing there is adriver wheel 2 a connected to a drive, for example a drive lever, as adrive element, as well as a claw like output element 3 a whose claws 31a, 32 a engage through window-like recesses 21 a, 21 a′ in the driverwheel and have a distance s from the edge of the window-like recesses 21a, 21 a′.

Two circular segment like locking elements 4 a, 4 a′ illustrated bycrossed hatching rest with their clamping faces 42 a, 42 a′, 42 a″, 42a′″ which protrude from the peripheral outer face of the lockingelements 4 a, 4 a′ against the cylindrical inside face of the adjustmenthousing 10 and each have two semi-circular recesses 43 a, 43 a′, 43 a″,43 a′″ in which engage the drive cams 22 a, 22 a′, 22 a″, 22 a′″ of thedriver wheel 2 a (illustrated by a thicker line) at a distance s fromthe wall of the semi circular like recesses 43 a, 43 a′, 43 a″, 43 a′″.

Facing the axis of the load moment lock 1 a, the locking elements 4 a, 4a′ have opposing expanding faces 41 a, 41 a′ each with protrusions orcurvatures 411 a, 411 a′; 412 a; 412 a′ formed symmetrical to the axisof symmetry of the load moment lock.

Between the locking elements 4 a, 4 a′ and the output element 3 a is aplay compensating device 5 a which lies by means of a spring 7 a underpretension between the two locking elements 4 a, 4 a′ and has the effectthat the semi circular like recesses 43 a, 43 a, 43 a″, 43 a′″ of thelocking elements 4 a, 4 a′ rest free of play (FIG. 2) against the drivecams 22 a, 22 a′, 22 a″, 22 a′″ of the driver wheel 2 a. The playcompensation between the drive element, the output element and the loadmoment lock is thus established with only one locking element pair inone plane. To see more clearly the play s which exists without theaction of the play compensating device 5 a, FIG. 1 shows the drive cams22 a, 22 a′, 22 a″, 22 a′″ of the driver wheel 2 a spaced by the play sfrom the semi circular recesses 43 a, 43 a′, 43 a″, 43 a′″ of thelocking elements 4 a, 4 a′. Through the action of the play compensatingdevice 5 a this play is eliminated and the drive cams 22 a, 22 a′, 22a″, 22 a′″ of the driver wheel 2 a lie as shown in FIG. 2 without playagainst the semi circular recesses 43 a, 43 a′, 43 a″, 43 a′″ of thelocking elements 4 a, 4 a′.

For this purpose the play compensating device 5 a has several wedgefaces 51 a, 51 a′; 52 a, 52 a′; 53 a, 53 a′ which rest against thecorresponding counter wedge faces 33 a, 33 a′; 34 a, 34 a′; 35 a, 35 a′of the output element 3 a. On the side facing the locking elements 4 a,4 a′ the play compensating device 5 a consists of flat or straightsurfaces 54 a, 54 a′ which at contact points A, A′, B, B′ contact theprotrusions or curvatures 411 a, 411 a′; 412 a; 412 a′ of the expandingsurfaces 41 a, 41 a′ of the locking elements 4 a, 4 a′.

The spring 7 a serving to pretension the play compensating device 5 a isthereby mounted between the angled ends 55 a, 55 a′ of the playcompensating device 5 a and an end face of the output element 3 a sothat the wedge faces 51 a, 51 a′; 52 a, 52 a′; 53 a, 53 a′ are movedparallel outwards i.e. to the locking elements 4 a, 4 a′ so that thelocking elements 4 a, 4 a′ are forced parallel outwards through thecontact bearing points A, A′, and B, B′.

The angle α between the wedge faces 51 a, 51 a′; 52 a, 52 a′; 53 a, 53a′ of the play compensating device 5 a and the counter wedge faces 33 a,33 a′; 34 a, 34 a′; 35 a, 35 a′ of the output element 3 a is selected sothat the play compensating device 5 a does not yield under stress, i.e.is displaced against the action of the spring 7 a.

The wedge faces 51 a, 51 a′; 52 a, 52 a′; 53 a, 53 a′ and counter wedgefaces 33 a, 33 a′; 34 a, 34 a′; 35 a, 35 a′ which bear against eachother under the action of the play compensating device 5 can be arrangedselectively on the play compensating device 5 a, on the output element 3a and/or on the locking elements 4 a, 4 a′. In all cases the lockingelements 4 a, 4 a′ move parallel outwards during resetting of the playcompensating device 5 a so that the play between the drive element 2 a,the output element 3 a and the load moment lock 1 a is eliminated or anelastic contact bearing of the drive cams 22 a, 22 a′, 22 a″, 22 a′″against the recesses 43 a, 43 a′, 43 a″, 43 a′″ of the locking elements4 a, 4 a′ is generated for transferring a drive moment.

The type of play compensation between the drive element 2 a, the outputelement 3 a and the load moment lock 1 a stems from large wedge pathsfor small paths of the locking elements 4 a, 4 a′ wherein the wedgeangle α is measured so that the play compensating device 5 a does notyield under stress and can be displaced against the action of the spring7 a.

When the adjustment device is operated, torque introduced on the driveside through the driver wheel 2 a as a result of the circular directedforce engagement which is further away from the rotational center leadsto a slight rotation of the locking elements 4 a, 4 a′ as a result ofthe torque transfer from the drive cams 22 a, 22 a′, 22 a″, 22 a′″ ofthe driver wheel 2 a to the recesses 43 a, 43 a′, 43 a″, 43 a′″ of thelocking elements 4 a, 4 a′ and then after overcoming the distance sbetween the claws 31 a, 32 a of the output element 3 a and thewindow-like recesses 21 a, 21 a′ of the driver wheel 2 a to a positivelocking connection between the claws 31 a, 32 a of the output element 3a and the window like recesses 21 a, 21 a′ of the driver wheel 2 a andthus to rotation of the output element 3 a.

Torque introduced on the output side through the output element 3 a onthe other hand, as a result of the more central and radially directedforce engagement of the output element 3 a, leads to forcing apart thelocking elements 4 a, 4 a′ as a result of the force engagement of theoutput element 3 a through the play compensation device 5 a and thecontact bearing points A, A′ and B, B′ respectively against theprotrusions or curvatures 411 a, 411 a′; 412 a; 412 a′ of the expandingfaces 41 a, 41 a′ of the locking elements 4 a, 4 a′ which leads to anintensification of the bearing force of the clamping faces 42 a, 42 a′,42 a″, 42 a′″ of the locking elements 4 a, 4 a′ against the adjustmenthousing 10 and thus to a blocking of the torque introduced on the outputside.

FIG. 2 shows an adjustment device with a load moment lock 1 b and anadjustment housing 10 in which similar to the embodiment described abovethere is a driver wheel 2 b connected to a drive as well as an outputelement 3 b whose claws 31 b, 32 b engage through window like recesses21 b, 21 b′ in the driver wheel 2 b. Two circular segment shaped lockingelements 4 b, 4 b′ bear with their clamping faces 42 b, 42 b′, 42 b″, 42b′″ against the adjustment housing 10. Drive cams 22 b, 22 b′, 22 b″, 22b′″ of the driver wheel 2 b engage through semicircular recesses 43 b,43 b′, 43 b″, 43 b′″ of the locking elements 4 b, 4 b′ and rest free ofplay against the edges of the semicircular recesses.

Between the locking elements 4 b, 4 b′ and the output element 3 b is aplay compensating device 5 b which is forced by means of a spring 7 bparallel between the two locking elements 4 b, 4 b′ and causes therecesses 43 b, 43 b′, 43 b″, 43 b′″ of the locking elements 4 b, 4 b′,to bear play free against the drive cams 22 b, 22 b′, 22 b″, 22 b′″ ofthe driver wheel 2 b. For this purpose the play compensating device 5 bhas two inclined bearing faces or wedge faces 51 b, 51 b′; 52 b, 52 b′with which it rests against cylindrical curvatures 36 b, 36 b′; 37 b, 37b′ of the output element 3 b.

The spring 7 b is mounted between the angled ends 55 b, 55 b′ of theplay compensating device 5 b and an output claw 32 b of the two outputclaws 31 b, 32 b of the output element 3 b and is designed as acompression spring so that the play compensating device 5 b is forcedbetween the cylindrical curvatures 36 b, 36 b′; 37 b, 37 b′ of theoutput element 3 b and the expanding faces 41 b, 41 b′ of the lockingelements 4 b, 4 b′ and thus an elastic contact bearing of the playcompensating device 5 b is generated against the output element 3 b onone side and the locking elements 4 b, 4 b′ on the other. The lockingelements 4 b, 4 b′ are moved parallel outwards by the play compensatingdevice 5 b so that the clamping faces 42 b, 42 b′; 42 b″, 42 b′″of thelocking elements 4 b, 4 b′ are forced radially against the adjustmenthousing 10.

The angle between the inclined contact bearing faces or wedge faces 51b, 51 b′, 52 b, 52 b′ of the play compensating device 5 b is selectedrelative to the axis of symmetry of the output element 3 b so that theplay compensating device 5 b does not yield under stress i.e. isdisplaced against the action of the spring 7 b.

The play compensation between the drive element 2 b formed as the driverwheel, the output element 3 b and/or the load moment lock 1 b takesplace similar to the embodiment according to FIG. 1 over large paths ofthe play compensating device 5 b with small paths of the lockingelements 4 b, 4 b′.

Similar to the functioning of the adjustment device of FIG. 1 describedabove torque introduced on the drive side through the driver wheel 2 bon account of the force engagement further away from the centre pointand directed circular leads to a slight rotation of the locking elements4 b, 4 b′ owing to the torque transfer from the drive cams 22 b, 22 b′,22 b″, 22 b′″ of the driver wheel 2 b to the recesses 43 b, 43 b′, 43b″, 43 b′″ of the locking elements 4 b, 4 b′ and then after overcomingthe distance between the drive cams 22 b, 22 b′, 22 b″, 22 b′″ and therecesses 43 b, 43 b′, 43 b″, 43 b′″ to a positive connection between theclaws 31 b, 32 b, of the output element 3 b and the window like recesses21 b, 21 b′ of the driver wheel 2 b and thus to rotation of the outputelement 3 b.

Torque introduced on the output side through the output element 3 bleads on the other hand owing to the more central and radially directedforce engagement of the output element 3 b to the locking elements 4 b,4 b′ being forced apart owing to the force engagement of the cylindricalcurvatures 36 b, 36 b′; 37 b, 37 b′ of the output element 3 b againstthe wedge faces 51 b, 51 b′, 52 b, 52 b′ of the play compensating device5 b and further through the rectilinear faces 54 b, 54 b′, 54 b″, 54 b′″of the play compensating device 5 b against the expanding faces 41 b, 41b′ of the locking elements 4 b, 4 b′ which leads to intensification ofthe contact bearing between the clamping faces 42 b, 42 b′, 42 b″, 42b′″ of the locking elements 5 b, 5 b′ and the adjustment housing 10 andthus to blocking of the torque introduced on the output side.

The embodiment illustrated in FIG. 3 corresponds to the adjustmentdevice according to FIG. 2 with the measure that the expanding faces 41c, 41 c′ of the locking elements 4 c, 4 c′ have inclined faces 411 c,411 c′, 412 c, 412 c′ against which corresponding wedge faces 51 c, 51c′; 52 c, 52 c′ of the play compensating device 5 c bear. Rectilinearfaces 54 c, 54 c′ of the play compensating device 5 c bear against thecylindrical curvatures 36 c, 36 c′, 37 c, 37 c′ of the output element 3c.

Also in this embodiment between the one output claw 31 c of the outputelement 3 c and the angled ends 55 c, 55 c′ of the play compensatingdevice 5 c there is a spring 7 c formed as a compression spring andproducing elastic contact between the wedge faces 51 c, 51 c′; 52 c, 52c′ of the play compensating device 5 c and the associated inclined faces411 c, 411 c′, 412 c, 412 c′ of the locking elements 4 c, 4 c′.

All the aforesaid adjustment devices have the basic function in common,namely in the event of drive torque acting in the direction of theoutput moment the lock established by the locking element is lifted butremains latently active so that an immediate locking action occurs whenthe drive torque is cancelled. If on the other hand the drive torqueacts against the output torque then the lock is lifted and the drivetorque is introduced into the output. A slight lifting or circularrotation of the locking element thereby takes place and then animmediate renewed contact bearing against the adjustment housing.

Through the wedge faces of a play compensating device bearing againstthe output element and/or against the locking elements in conjunctionwith the pretensioning force of a spring which pretensions the playcompensating device perpendicular to the axis of the load moment lock inthe sense of reducing the distance between the play compensating device,the output element and the locking elements, the locking element facesare constantly brought in contact bearing against the cylindricaladjustment housing and thus optimum rotational angle play is guaranteedwhen setting up and even after long service use of the adjustmentdevice.

What is claimed is:
 1. An adjustment device for producing a rotationalmovement, comprising: a cylindrical adjustment housing; a drive element;an output element which is adjustable at an angle by operating the driveelement; a load moment lock mounted between the drive element and theoutput element which blocks, through force engagement, torque introducedon an output side to a drive side and transfers torque introduced on thedrive side to the output element, wherein the load moment lock haslocking elements mounted in the cylindrical adjustment housing, thelocking elements having clamping faces and opposing faces; a playcompensating device mounted at least in part between the opposing facesof the locking elements which compensates the rotational angle playbetween the drive element, the output element and the load moment lockand which forces apart the clamping faces with such force that they restwith predetermined pretension against the adjustment housing, whereinthe play compensating device for both rotational directions radiallyforces apart the locking elements mounted in one plane of the loadmoment lock in a direction perpendicular to an axis of the load momentlock, and wherein the play compensating device has wedge faces whichrest against at least one of the output element and the lockingelements, and at least one spring which pretensions the playcompensating device perpendicular to the axis of the load moment lock inthe sense of reducing the distance between the play compensating device,the output element and the locking elements.
 2. An adjustment deviceaccording to claim 1 wherein the wedge faces include such an angle withan axis of symmetry of the load moment lock that the connection betweenthe play compensating device on one side and the at least one of theoutput element and the locking elements on the other is self-locking. 3.An adjustment device according to claim 1 or 2 wherein the wedge facesof the play compensating device bear against counter wedge faces of theoutput element and substantially flat faces of the play compensatingdevice bear against one of opposing faces of the locking elements andparts of the opposing faces.
 4. An adjustment device according to claim1 or 2 wherein the output element has protrusions or curvatures formedsymmetrical to the axis of symmetry of the load moment lock for spot orlinear contact of substantially rectilinear or inclined faces of theplay compensating device.
 5. An adjustment device according to claim 4wherein the wedge faces of the play compensating device bear against theprotrusions or curvatures of the output element arranged symmetricalrelative to the axis of symmetry of the load moment lock and thesubstantially rectilinear surfaces of the play compensating device bearagainst the opposing faces of the locking elements or parts of theopposing faces.
 6. An adjustment device according to claim 4 wherein thewedge faces of the play compensating device bear against inclinedexpanding faces of the locking elements and the substantiallyrectilinear faces of the play compensating device bear against theprotrusions or curvatures of the output element.
 7. An adjustment deviceaccording to claim 1 wherein the drive element has recesses which withtorque on the drive side after lifting the frictional contact of thelocking elements against the adjustment housing bear with positiveengagement against claws of the output element and entrain same in thedrive direction.